1. Field of the Invention
The present invention relates to silver halide photographic materials. More particularly, the present invention relates to a silver halide photographic materials containing a compound adapted to make available a photographically useful group in photographic development.
2. Description of the Prior Art
Compounds are known which are able to release photographically useful groups through oxidation-reduction reactions.
Examples include hydroquinone derivatives adapted to release development inhibitors, as described, e.g., in U.S. Pat. Nos. 3,379,529, 3,620,746, 4,144,071, 4,377,634 and 4,332,878.
Examples of hydroquinone derivatives which release silver halide solvents are described in U.S. Pat. No. 4,459,351.
Examples of hydroquinone derivatives adapted to release diffusible dyes are described in U.S. Pat. Nos. 3,698,897 and 3,725,062.
As described in the above-mentioned patents, the compounds heretofore known are used for various purposes depending on the types of their photographically useful groups. In color photographic light-sensitive materials, in particular, hydroquinone compounds adapted to release a development inhibitor have been used effectively for the improvement of sharpness, granularity, and color reproduction. However, in order to meet increasingly sophisticated and complex photographic requirements, the conventional compounds are not satisfactory and further improvements have been required.
Thus, it is undeniably true that in recently formulated high-sensitivity color photographic light-sensitive materials, sharpness and granularity have been more or less sacrificed in order to increase the sensitivity. Moreover, in the disk size film, which requires a high magnification factor for printing, graininess and sharpness have not been as satisfactory as desired.
In silver halide photographic materials for photoengraving use, compounds capable of providing further improvements in dot quality have been strongly desired.
Furthermore, in black-and-white photographic light-sensitive materials for X-ray use, materials conductive to improved sharpness have also been strongly desired.